Process for the production of aromatic dinitrohalogen compounds

ABSTRACT

Aromatic dinitrohalogen compounds are prepared by reacting aromatic dinitrohydroxy compounds with an acid halide such as phosgene in the presence of an acylated secondary amine as a catalyst at a temperature of from about 50* to 200*C.

United States Patent [191 Blahak et a1.

[ March 6, 1973 PROCESS FOR THE PRODUCTION OF AROMATIC DINITROHALOGENCOMPOUNDS Inventors: Johannes Blahak, Cologne, Germany; Walter Meckel,Martinsville, United States Of America Farbenfabriken BayerAktiengesellschait, Leverkusen, Germany Filed: Jan. 5, 1971 AppLNo;104,144

Assignee:

Foreign Application Priority Data Jan. 15, 1970 Germany ..P 20 01 570.7

US. Cl ..260/646, 260/456 P, 260/476 R,

260/592, 260/607 A Int. Cl. ..C07c 79/12, C07c 139/00 [58] Field ofSearch ..260/646, 456 P, 476 R, 592,

Primary Examiner-Leland A. Sebastian Attorney-Burgess, Dinklage & Sprung[57] ABSTRACT Aromatic dinitrohalogen compounds are prepared by reactingaromatic dinitrohydroxy compounds with an acid halide such as phosgenein the presence of an acylated secondary amine as a catalyst at atemperature of from about 50 to 200C.

12 Claims, No Drawings PROCESS FOR THE PRODUCTION OF AROMATICDINITROHALOGEN COMPOUNDS BACKGROUND This invention relates to aparticularly advanced process for the production of aromaticdinitrohalogen compounds by reacting corresponding hydroxy compoundswith acid halides in the presence of catalytic quantities of an acylatedsecondary amine.

it is known that aromatic polynitrohalogen compounds can be obtainedfrom corresponding polynitrohydroxy compounds by replacing with halogenthe hydroxy groups which are activated by nitro groups. Preferredexchange reagents are acid chlorides in the presence of equimolarquantities of a tertiary amine. One preferred process uses p-toluenesulphochloride in the presence of a molar amount of diethyl aniline. Theyields obtained are from about 60 to 80 percent of the theoretical (seel-louben-Weyl, Methoden der organischen Chemie, 1962, Vol. V/3, page896).

SUMMARY A process has now been found for the production of aromaticdinitrohalogen compounds by reacting corresponding dinitrohydroxycompounds with acid halides in the presence of catalysts wherein anaromatic hydroxy compound having up to 14 ring carbon atoms in thearomatic portion and containing up to two hydroxy groups at least onewhich is activated by at least two nitro groups in the ortho-positionsto the OH group or in the orthoand para-positions to the OH group, whileup to three of the remaining hydrogen atoms of the aromatic hydroxycompound can also be substituted by similar or different radicals, suchas halogen, alkyl, COO-alkyl, CO-alkyl, sO -alkyl, CF or SO, -alkylradicals, is reacted with at least the stoichiometrically necessaryquantity of an acid halide in the presence of a catalytic quantity of anacylated secondary amine, at a temperature in the range from about 50 toabout 200C DESCRIPTION in which R represents hydrogen, alkyl with one tosix carbon atoms, or a group of the formula R O-R or N and the radicalsR, R and R, which can be the same 'or different, each represents analkyl radical with one to four carbon atoms or the radicals R and R,together with the nitrogen atom to which they are attached, or theradicals R and R, together with the group can form a 5- to 7-memberedring, optionally containing a further hetero atom or atoms.

Hetero atoms include oxygen, sulphur and a nitrogen atom substituted bya lower alkyl radical (up to four carbon atoms). Dimethyl formamide is aparticularly preferred carboxylic acid amide for carrying out theprocess according to the invention.

The catalyst is added in a concentration of from 0.1 to 50 percent byweight, and preferably in a concentration of from 1 to 10 percent byweight, based on the starting aromatic hydroxy compound.

Acid halides include thionyl chloride and thionyl bromide, although inprinciple it is also possible to use other acid halides, for exampleacetyl chloride, acetyl bromide, oxalyl chloride, oxalyl bromide orp-toluene sulphochloride; preferably phosgen is used.

The process can be carried out either in solution or, in some instances,even in the melt, at temperatures in the range of from 50 to 200C.. Thehydroxy compound used is preferably dissolved in an inert organicsolvent, for example benzene, toluene, xylene, chlorobenzene oro-dichlorobenzene, and then reacted with the acid halide, following theaddition of e. g. approximately 5 percent by weight of the catalyst. Thereaction is preferably carried out temperatures of from to C. To carryout the process, the acid halide is generally used in at least thestoichiometrically necessary quantity per OH-group to be exchanged, butpreferably in an excess of up to about 20 percent by weight. Instead ofworking in an inert solvent, it is, of course, also possible in someinstances, to work in an excess of acid halide, providing it boils attemperatures above 50C.. In a preferred embodiment the reaction iscarried out at the boilingpoint of the reaction mixture.

The process according to the invention can be carried out with aromaticcompounds based on benzene, naphthalene or a fused three ring compoundsuch as anthraca. Preferred are benzene compounds. Each has at least one-OH group and, in addition to the activating nitro groups, one or two,preferably one, other ring substituent identified above.

The starting compounds used in the process according to the inventioncan be represented by the general formulas l and II, the2,6-dinitrophenols (ll) being preferred:

I OH

---NO: N0 N02 x No; n

in these formulas,

X (in addition to hydrogen) represents halogen (preferably fluorine,chlorine or bromine), alkyl, COO-alkyl, CO-alkyl, SO alkyl, CF, orSO,-alkyl, the alkyl radicals having I to 10, preferably 1 to 6, andmost preferably one or two carbon atom s, and

n represents 1, 2 or 3.

The following are but a few examples of starting compounds that maypreferably be used for the process according to the invention:

The process is illustrated by the following equation:

The following are examples of the compounds which can be obtained by theprocess according to the invention:

C1 Cl C OzNQ-NOZ NOQ-NO: OzN l Br The yields amount to from 90 to 100percent. The advantage of the process according to the invention Thefact that the process according to the invention can be carried out sosmoothly must be regarded as extremely surprising, because it had beenassumed from the prior art that carbonates and carbonic acid esterchlorides would be formed. See J. American Chem. Soc. 56, 1586 (1934).

The dinitrocompounds obtainable by the process according to theinvention can be converted by the usual methods into the correspondingamines, which can be used for the production of dyes (D.R.P. 177 623),plant-protection (U.S. Pat. No. 3,257,190) agents etc.

In the following examples, temperature are expressed in degreesCentigrade.

Example 1 (method A) 20 g. of thionyl chloride and 20 g. of4-chloro-2,6- dinitrophenol are dissolved in 200 ml. of benzene.Following the addition of 1.5 g. of dimethyl formamide, the mixture isbrought to the boil. A vigorous evolution of hydrogen chloride andsulphur dioxide begins at C.. After 1 hour, the excess thionly chlorideis distilled off. The crystalline residue is taken up in benzene andwashed three times with ml. of water. The solvent is distilled off. Therequired compound, 1,4-dichlor0-2,o-dinitrobenzene, is obtained in ayield of 21 g. (100 percent), m.p. l0l-l03C.. After recrystallizationfrom ethanol, it melts at l04l05C. (lit. m.p. l04- -l05C.).

Example 2 (method B) 20 g. of 4-chloro-2,fi-dinitrophenol are heatedunder reflux in 200 ml. of xylene to which 2 g. of dimethyl formamidehave added, accompanied by the introduction of phosgenej The reaction,which actually begins below 100C., is over after 30 minutes at 140C..Excess phosgene is removed by a vigorous stream of nitrogen. The product1,4 dichloro-2,6-dinitrobenzene is left in an almost quantitative yieldof 21 g. (97 percent of the theoretical), m.p. l05-107C. from ethanol.

The following compounds are similarly obtained:

20 g. of 4-hydroxy-3,5-dinitrotoluene are dissolved in 200 ml. ofxylene. Following the addition of 1.5 g. of tetramethyl urea, phosgeneis introduced at 100 to 140C.. After 2 hours, the reaction is complete.

By working up the reaction as described in Example 1,4-ch1oro-3,S-dinitrotoluene is obtained in a yield of 90 percent (m.p.1l2-114C.).

Example 11 2 g. of dimethyl formamide and 20 g. of 2-hydroxy-3,5-dinitrotoluene are dissolved in 200 ml. of odichlorobenzene.Following the addition of 1.5 g. of dimethyl formamide, phosgene isintroduced at 160C.. The reaction is quantitative after 3 hours.

By working up the reaction mixture as described in Example 1,2-chlor0-3,S-dinitrotolucne is obtained in a yield of 74 percent (m.p.63C.).

Example 12 The procedure is as in Example 2, except that the reaction iscarried out with 25 g. of 4-ch1oro-2,6- dinitrotoluene in 250 ml. ofxylene, using 2 g. of tetramethyl urea as catalyst. The reaction iscomplete after heating for 1 hour at 140C.,. The yieldof 1,4-dichloro-3,S-dinitrobenzene is 27 g. (approximately l00% of thetheoretical), m.p. 103-105C..

What we claim is:

1. A process for the production of aromatic dinitrohalogen compoundswhich comprises reacting an aromatic dinitrohydroxy compound containingup to 14 ring carbon atoms in the aromatic portion and cally necessaryquantity of phosgene in the presence of an acylated secondary amine ascatalyst at a temperature in the range from about 50 to about 200C..

2. A process as claimed in claim 1, wherein the catalyst comprises from0.1 to 50 percent by weight,

based on the dinitrohydroxy compound, of a carboxylic acid amide of thegeneral formula in which R represents hydrogen, alkyl with one to sixcarbon atoms, or a group of the formula and the radicals R, R and R,which can be the same or different, each represents an alkyl radicalwith one to four carbon atoms, or the radicals R and R, together withthe nitrogen atom to which they are attached, or the radicals R and R,together with the grouping form a 5- to 7-membered ring.

3. A process as claimed in claim 1 wherein said 5- to 7-membered ringcontains at least one hetero atom.

4. A process as claimed in claim 1 wherein the catalyst is dimethylformamide.

5. A process as claimed in claim 1 wherein the catalyst is used in anamount of from 1 to 10 percent by weight, based on the dinitrohydroxycompound.

6. A process as claimed in claim 1 wherein the temperature is from aboutto about C..

7. A process as claimed in claim 1 wherein the catalyst is tetramethylurea.

8. A process as claimed in claim 1 wherein the dinitrohydroxy compoundshas the general formula M NO:

in which each symbol X, which may be the same or different, representshalogen, alkyl, COO-alkyl, CO-alkyl, SO -alkyl, CF; or SO alkyl, thealkyl radicals having 1 to 10 carbon atoms, and n represents 1, 2 or 3.

9. A process as claimed in claim 1 wherein the dinitrohydroxy compoundhas the general formula OH N01 WNOQ in which each symbol X, which may bethe same or different, represents halogen, alkyl, COO-alkyl, CO-alkyl,SO,-alkyl, CF, or SO,-alkyl, the alkyl radicals having 1 to 10 carbonatoms, and n represents 1, 2 or 3.

10. A process as claimed in claim 1 wherein the reaction is carried outin solution in an inert organic solvent.

11. A process as claimed in claim 10 wherein the solvent is selectedfrom the group of benzene, toluene, xylene, chlorobenzene ando-dichlorobenzene.

12. A process as claimed in claim 1 wherein phosgene is used in anexcess of up to 20 percent by weight.

i i t 8 I

1. A process for the production of aromatic dinitrohalogen compoundswhich comprises reacting an aromatic dinitrohydroxy compound containinguP to 14 ring carbon atoms in the aromatic portion and having one or twohydroxy at least one of which is activated by at least two nitro groupsortho- or ortho- and para-to the -OH group with at least thestoichiometrically necessary quantity of phosgene in the presence of anacylated secondary amine as catalyst at a temperature in the range fromabout 50* to about 200*C..
 2. A process as claimed in claim 1, whereinthe catalyst comprises from 0.1 to 50 percent by weight, based on thedinitrohydroxy compound, of a carboxylic acid amide of the generalformula in which R represents hydrogen, alkyl with one to six carbonatoms, or a group of the formula and the radicals R1, R2 and R3, whichcan be the same or different, each represents an alkyl radical with oneto four carbon atoms, or the radicals R1 and R2, together with thenitrogen atom to which they are attached, or the radicals R1 and R,together with the grouping form a 5- to 7-membered ring.
 3. A process asclaimed in claim 1 wherein said 5- to 7-membered ring contains at leastone hetero atom.
 4. A process as claimed in claim 1 wherein the catalystis dimethyl formamide.
 5. A process as claimed in claim 1 wherein thecatalyst is used in an amount of from 1 to 10 percent by weight, basedon the dinitrohydroxy compound.
 6. A process as claimed in claim 1wherein the temperature is from about 75* to about 150*C..
 7. A processas claimed in claim 1 wherein the catalyst is tetramethyl urea.
 8. Aprocess as claimed in claim 1 wherein the dinitrohydroxy compounds hasthe general formula in which each symbol X, which may be the same ordifferent, represents halogen, alkyl, COO-alkyl, CO-alkyl, SO3-alkyl,CF3 or SO2-alkyl, the alkyl radicals having 1 to 10 carbon atoms, and nrepresents 1, 2 or
 3. 9. A process as claimed in claim 1 wherein thedinitrohydroxy compound has the general formula in which each symbol X,which may be the same or different, represents halogen, alkyl,COO-alkyl, CO-alkyl, SO3-alkyl, CF3 or SO2-alkyl, the alkyl radicalshaving 1 to 10 carbon atoms, and n represents 1, 2 or
 3. 10. A processas claimed in claim 1 wherein the reaction is carried out in solution inan inert organic solvent.
 11. A process as claimed in claim 10 whereinthe solvent is selected from the group of benzene, toluene, xylene,chlorobenzene and o-dichlorobenzene.